Buffer structure

ABSTRACT

A buffer structure in which a plurality of buffer bodies separated from each other by intermediate disc means are in axial direction located one behind the other and with radial play are arranged in a tubular member which has one end closed and has a push rod slidably arranged in the other end portion of the tubular member. The disc means are preferably provided with peripheral annular flange means slidably engaging the inner wall surface of the tubular member and defining annular grooves receiving therein portions of adjacent buffer bodies.

United States Patent 1 1 Sehwarz 1 June 24, 1975 BUFFER STRUCTURE FOREIGN PATENTS OR APPLICATIONS I lnvenwrl Wilhelm Schwarh wilhclmshlwm 1,904.668 8 1970 Germany 267 140 Germany [73] Assignee: Fried. Krupp GmhH. Essen. Primary E.\'umin0rJames B. Marbert Germany Attorney Agent. or FirmWalter Becker [ZZj Filed: Mar. 12, 1974 l2] Appl. No.: 450,309 ABSTRACT A buffer structure in which a plurality of buffer bodies separated from each other by intermediate disc means Appl'camm Pmmy Dam are in axial direction located one behind the other and Mar. 17 W73 Germany t. 2313389 with radial play are arranged in a tubular member which has one end closed and has a push rod slidably [52] U-S- Cl. 293/88 arranged in the other end portion of the tubular mem [Sl Int. Cl Flfif 7/08 ber The disc means are preferably provided with pel l Field 0f Search ripheral annular flange means slidably engaging the 293/38 inner wall surface of the tubular member and defining annular grooves receiving therein portions of adjacent [56] References Cited buffer bodies.

UNITED STATES PATENTS 4 Claims, 3 Drawing Figures 3.774.951 11/1973 Church ct 111. 293/88 BUFFER STRUCTURE The present invention relates to a buffer structure. Buffer bodies of cellular elastic material have over bodies with a high modulus of elasticity such as compact bodies of rubber, wood, or steel the disadvantage that they easily buckle under pressure load when the pressed body has a length which is relatively high in comparison to its diameter. This danger of buckling exists already when cellular elastic buffer bodies which are highly porous have a length which only exceeds twice the diameter of the body. Also when a correspondingly long buffer body of circular material is inserted into a tube, a situation occurs which is similar to buckling. Due to the fact that the buffer body in its starting position has to have a radial play with regard to the tube, the long buffer body will under the effect of a buffer shock deform also in a direction transverse to the direction in which the shock occurs and more specifically will deform in an undulated or zigzag manner so that it will engage the inner surface of the tube at approximately equal longitudinal distances. This results in a jamming of the buffer body so that the desired buffer line of characteristics cannot be realized and the buffer body will have only an insufficient span of useful life.

It is, therefore, an object of the present invention to provide a buffer structure for long buffer strokes, as they are required for obtaining a high work receiving capability as is needed for instance with airplane towaway bars and with cable line buffers of cable cars, with buffer bodies of cellular material which are guided in a tube while the arrangement will prevent the above mentioned difficulties.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 is a section through a buffer according to the present invention.

FIGS. 2 and 3 respectively illustrate two cut-outs of buffers of two different embodiments according to the invention.

The buffer structure according to the present invention which is intended for long buffer strokes and comprises buffer bodies of a cellular material guided in a tube is characterized primarily in that intermediate elements guided in the tube are interposed between the buffer bodies which when not under load have a radial play relative to the inner surface of the tube.

The buffer structure according to the present invention has the advantage that the material of the buffer bodies, although the latter permit considerable buffer strokes will be treated carefully. The relatively short buffer bodies which in unloaded condition have a radial play relative to the tube can similar to the intermediate members for guiding the buffer bodies easily be built into the tube so that the exchange of worn out buffer bodies can be easily and efficiently effected.

When according to a preferred embodiment of the invention the intermediate members consist of discs with flanges engaging the inner surface of the tube, the additional advantage will be realized that the buckling length of each of the buffer bodies will be reduced by the width of the flanges.

Referring now to the drawing in detail and FIG. 1 thereof in particular, the buffer structure shown in FIG.

1 comprises three buffer bodies 1 of a cellular material for instance foamed polyurethane, said buffer bodies 1 being inserted into a tube 2 one behind the other. One end of the tube 2 has welded thereon a connecting plate 3. The outer diameter of the buffer body 1 is in its condition in which it is under no load, shorter than the inner diameter of the tube 2 so that the buffer bodies l have a radial play 4 relative to the inner surface of the tube 2.

Between the buffer body 1 which when under no load have a length 1 there are inserted intermediate members 5 which have an I-profile. These intermediate members 5 each comprise a disc 6 and an annular flange 7 which engages the inner surface of the tube 2. The annular flanges which have a width b taper toward their free ends. However, it is also possiblethat they have the same thickness over their entire widthr'Qne end of the buffer bodies 1 extends into the hollow space formed on both sides of the disc 6 between thetrespective adjacent flanges 7. In a corresponding manner, that buffer body 1 which is closest to the connecting or closure plate 3 fits into a correspondingly shaped depression in a push rod 8.

Consequently, the free length 1 of each of the buffer bodies 1 is when said buffer bodies are under no load shorter by the width b of the annular flange 7.

It will be appreciated that for this reason the buffer bodies 1 will not buckle when subjected to shocks so that they cannot in a harmful manner unilaterally or alternately one after another be deformed to one or the other side. Instead, the buffer bodies will be upset by a shock load in such a way that their diameter will increase uniformly to all sides. Preferably this occurs to such an extent that the buffer bodies will over their entire circumference engage the inner surface of the tube 2. The friction created in this way results in a desired cushioning of the buffer.

Since due to the annular flanges 7 the free length l of the buffer body 1 is shorter by the width b than the length 1 the intermediate members 5 can be arranged in greater distances from each other than would be the case if they were formed by discs without flanges. In this way considerable material is saved. The tube 2 and consequently also the annular flanges 7 and the push rod 8 may have a circular cross section or any other suitable cross section for instance square shaped cross section or polygonal cross section. The intermediate members 5 or if desired only the annular flanges 7 may consists of elastic material such as any suitable synthetic plastic material. In such an instance, as shown in FIG. 2, it is advantageous to provide sealing lips 9 (FIG. 2) near the edges of the annular flanges 7 which sealing lips engage the inner surface of tube 2 and prevent cellular material from entering the space between the annular flanges 7 and the tube 2 when the buffer bodies are upset into a shape indicated by dot-dash lines in FIG. 2.

According to FIG. 3, an intermediate member is built up of two pot-shaped sections 10 of sheet metal the bottoms of which engage each other and are connected to each other in any suitable manner for instance by riveting or screws so that they will together with the portions engaging the inner surface of tube 2 from an I-profile.

If the buffer structure is to be subjected to frequent shock loads, the intermediate members 5, 10 are expediently made of a material which is a good heat conductor so that .the heat which develops due to the shock loads can properly be conducted away from the inside toward the outside.

It is, of course, to be understood that the present invention is, by no means, limited to the specific showing in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

l. A buffer structure for relatively large buffer strokes, which includes: a tubular member having hollow chamber space therein, a plurality of buffer bodies including ends thereof arranged axially one behind the other in said tubular member, said buffer bodies comprising cellular elastic material and when under no load having a radial play with regard to the inner surface of said tubular member so as to be able to radially expand when being subjected to an axial load, closure means including hollow space. therewith connected to and closing one end of said tubular member, a plurality of intermediate elements slidably arranged within said tubular member and respectively interposed between each two adjacent ones of said buffer bodies, the other end of said tubular member being open, and push rod means with hollow space at an end thereof slidably guided by said open end of said tubular member and adapted to engage the respective adjacent end portion of the respective adjacent buffer body for elastically compressing the latter and the other buffer bodies in said tubular member in response to an axial load acting upon said push rod means in the direction toward said closure means, said intermediate elements comprising discs with annular flange means slidably engaging the inner wall surface ofrsaid tubular member, said ends of the buffer bodies being inserted in the hollow chamber space formed by the discs and flange means as well as in the hollow space of the closure means on one end of said tubular member and into hollow space of the end of said push rod means extending into said tubular member, said annular flange means extending on opposite sides of the pertaining discs.

2. A buffer structure according to claim 1, in which said annular flange means consist of an elastic material and include sealing means sealingly engaging the respective adjacent inner wall portions of said tubular member.

3. A buffer structure according to claim 1, in which at least some of said intermediate elements include two sections connected to each other and each defining an annular groove, the grooves of each two interconnected sections respectively opening in opposite direction.

4. A buffer structure according to claim 1, in which said annular flange means respectively define annular groove means respectively having a portion of an adjacent buffer body located therein. 

1. A buffer structure for relatively large buffer strokes, which includes: a tubular member having hollow chamber space therein, a plurality of buffer bodies including ends thereof arranged axially one behind the other in said tubular member, said buffer bodies comprising cellular elastic material and when under no load having a radial play with regard to the inner surface of said tubular member so as to be able to radially expand when being subjected to an axial load, closure means including hollow space therewith connected to and closing one end of said tubular member, a plurality of intermediate elements slidably arranged within said tubular member and respectively interposed between each two adjacent ones of said buffer bodies, the other end of said tubular member being open, and push rod means with hollow space at an end thereof slidably guided by said open end of said tubular member and adapted to engage the respective adjacent end portion of the respective adjacent buffer body for elastically compressing the latter and the other buffer bodies in said tubular member in response to an axial load acting upon said push rod means in the direction toward said closure means, said intermediate elements comprising discs with annular flange means slidably engaging the inner wall surface of said tubular member, said ends of the buffer bodies being inserted in the hollow chamber space formed by the discs and flange means as well as in the hollow space of the closure means on one end of said tubular member and into hollow space of the end of said push rod means extending into said tubular member, said annular flange means extending on opposite sides of the pertaining discs.
 2. A buffer structure according to claim 1, in which said annular flange means consist of an elastic material and include sealing means sealingly engaging the respective adjacent inner wall portions of said tubular member.
 3. A buffer structure according to claim 1, in which at least some of said intermediate elements include two sections connected to each other and each defining an annular groove, the grooves of each two interconnected sections respectively opening in opposite direction.
 4. A buffer structure according to claim 1, in which said annular flange means respectively define annular groove means respectively having a portion of an adjacent buffer body located therein. 